Fine particle pollution in seven New York City locations
The air in New York on Wednesday wasn’t just bad by city standards. It’s been historically bad, even compared to places around the world that generally experience far more air pollution.
The graph above shows the concentration of a particularly dangerous type of air pollution, as measured by the state Department of Environmental Conservation from a network of sensors scattered around the city.
Those sensors measured levels of particles 2.5 microns in diameter or smaller, blown by wildfires in Canada. Wednesday’s daily average was the highest since recordings began in New York in 1999. (The second highest level was on Tuesday). Fires were raging in Northern California and approaching average pollution levels recorded in Portland, Oregon on Sept. 13, 2020, during the worst pollution from nearby wildfires.
The small particles measured by the sensors, each about one-thirtieth as wide as a human hair, are dangerous to human health because they are small enough to enter the lungs and bloodstream. The Environmental Protection Agency closely follows pollution of this type from smokestacks and vehicles.
Thirty-five micrograms of particles per cubic meter of air is considered a safe average level in the air for one day, according to the agency. Wednesday’s average level at seven of the city’s stations was 377, nearly 11 times that threshold.
Wednesday’s pollution, of course, was not caused by a power plant or vehicles, but by major fires in Canada, mostly in Quebec. Fires of this magnitude are unusual in eastern North America, said Eric James, a research associate at the University of Colorado who works on the model used by the National Oceanic and Atmospheric Administration to predict the movement of smoke from wildfires. The east coast tends to get more rain in the summer than the western half of the continent, where wildfires are so common they have a season. An unusual weather pattern pushing pollution along the coast is also a culprit, he said.
Source: National Oceanic and Atmospheric Administration
How long the air will remain hazardous depends on what happens with the fires, the weather in Canada and the wind. Meteorologists trying to predict air quality struggle to make very accurate estimates beyond a 48-hour window, James said. Their models are based on satellite measurements of fire intensity, but they don’t predict whether fires will get better or worse over time, beyond a typical pattern of growing slightly more intense during the hot part of the day and slightly weaker during the Night.
Predicting the wind that moves the smoke is also a challenge, particularly during the summer. Wind during the winter tends to be more predictable. Summer winds are often produced by thunderstorms, which are small, local, and typically of short duration. The New York area could see improvement Thursday and Friday with smoke expected to drift south and west, the National Weather Service said, but any major changes may not occur until early next week.
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